Spring Framework example source code file (BeanDefinitionVisitor.java)

This example Spring Framework source code file (BeanDefinitionVisitor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

beandefinitionholder, beandefinitionvisitor, constructorargumentvalues, iterator, iterator, object, object, propertyvalue, runtimebeanreference, runtimebeanreference, string, string, stringvalueresolver, typedstringvalue, util

The Spring Framework BeanDefinitionVisitor.java source code

/*
 * Copyright 2002-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.config;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyValue;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringValueResolver;

/**
 * Visitor class for traversing {@link BeanDefinition} objects, in particular
 * the property values and constructor argument values contained in them,
 * resolving bean metadata values.
 *
 * <p>Used by {@link PropertyPlaceholderConfigurer} to parse all String values
 * contained in a BeanDefinition, resolving any placeholders found.
 *
 * @author Juergen Hoeller
 * @since 1.2
 * @see BeanDefinition
 * @see BeanDefinition#getPropertyValues
 * @see BeanDefinition#getConstructorArgumentValues
 * @see PropertyPlaceholderConfigurer
 */
public class BeanDefinitionVisitor {

	private StringValueResolver valueResolver;


	/**
	 * Create a new BeanDefinitionVisitor, applying the specified
	 * value resolver to all bean metadata values.
	 * @param valueResolver the StringValueResolver to apply
	 */
	public BeanDefinitionVisitor(StringValueResolver valueResolver) {
		Assert.notNull(valueResolver, "StringValueResolver must not be null");
		this.valueResolver = valueResolver;
	}

	/**
	 * Create a new BeanDefinitionVisitor for subclassing.
	 * Subclasses need to override the {@link #resolveStringValue} method.
	 */
	protected BeanDefinitionVisitor() {
	}


	/**
	 * Traverse the given BeanDefinition object and the MutablePropertyValues
	 * and ConstructorArgumentValues contained in them.
	 * @param beanDefinition the BeanDefinition object to traverse
	 * @see #resolveStringValue(String)
	 */
	public void visitBeanDefinition(BeanDefinition beanDefinition) {
		visitParentName(beanDefinition);
		visitBeanClassName(beanDefinition);
		visitFactoryBeanName(beanDefinition);
		visitFactoryMethodName(beanDefinition);
		visitScope(beanDefinition);
		visitPropertyValues(beanDefinition.getPropertyValues());
		ConstructorArgumentValues cas = beanDefinition.getConstructorArgumentValues();
		visitIndexedArgumentValues(cas.getIndexedArgumentValues());
		visitGenericArgumentValues(cas.getGenericArgumentValues());
	}

	protected void visitParentName(BeanDefinition beanDefinition) {
		String parentName = beanDefinition.getParentName();
		if (parentName != null) {
			String resolvedName = resolveStringValue(parentName);
			if (!parentName.equals(resolvedName)) {
				beanDefinition.setParentName(resolvedName);
			}
		}
	}

	protected void visitBeanClassName(BeanDefinition beanDefinition) {
		String beanClassName = beanDefinition.getBeanClassName();
		if (beanClassName != null) {
			String resolvedName = resolveStringValue(beanClassName);
			if (!beanClassName.equals(resolvedName)) {
				beanDefinition.setBeanClassName(resolvedName);
			}
		}
	}

	protected void visitFactoryBeanName(BeanDefinition beanDefinition) {
		String factoryBeanName = beanDefinition.getFactoryBeanName();
		if (factoryBeanName != null) {
			String resolvedName = resolveStringValue(factoryBeanName);
			if (!factoryBeanName.equals(resolvedName)) {
				beanDefinition.setFactoryBeanName(resolvedName);
			}
		}
	}

	protected void visitFactoryMethodName(BeanDefinition beanDefinition) {
		String factoryMethodName = beanDefinition.getFactoryBeanName();
		if (factoryMethodName != null) {
			String resolvedName = resolveStringValue(factoryMethodName);
			if (!factoryMethodName.equals(resolvedName)) {
				beanDefinition.setFactoryMethodName(resolvedName);
			}
		}
	}

	protected void visitScope(BeanDefinition beanDefinition) {
		String scope = beanDefinition.getScope();
		if (scope != null) {
			String resolvedScope = resolveStringValue(scope);
			if (!scope.equals(resolvedScope)) {
				beanDefinition.setScope(resolvedScope);
			}
		}
	}

	protected void visitPropertyValues(MutablePropertyValues pvs) {
		PropertyValue[] pvArray = pvs.getPropertyValues();
		for (int i = 0; i < pvArray.length; i++) {
			PropertyValue pv = pvArray[i];
			Object newVal = resolveValue(pv.getValue());
			if (!ObjectUtils.nullSafeEquals(newVal, pv.getValue())) {
				pvs.addPropertyValue(pv.getName(), newVal);
			}
		}
	}

	protected void visitIndexedArgumentValues(Map ias) {
		for (Iterator it = ias.values().iterator(); it.hasNext();) {
			ConstructorArgumentValues.ValueHolder valueHolder =
					(ConstructorArgumentValues.ValueHolder) it.next();
			Object newVal = resolveValue(valueHolder.getValue());
			if (!ObjectUtils.nullSafeEquals(newVal, valueHolder.getValue())) {
				valueHolder.setValue(newVal);
			}
		}
	}

	protected void visitGenericArgumentValues(List gas) {
		for (Iterator it = gas.iterator(); it.hasNext();) {
			ConstructorArgumentValues.ValueHolder valueHolder =
					(ConstructorArgumentValues.ValueHolder) it.next();
			Object newVal = resolveValue(valueHolder.getValue());
			if (!ObjectUtils.nullSafeEquals(newVal, valueHolder.getValue())) {
				valueHolder.setValue(newVal);
			}
		}
	}

	protected Object resolveValue(Object value) {
		if (value instanceof BeanDefinition) {
			visitBeanDefinition((BeanDefinition) value);
		}
		else if (value instanceof BeanDefinitionHolder) {
			visitBeanDefinition(((BeanDefinitionHolder) value).getBeanDefinition());
		}
		else if (value instanceof RuntimeBeanReference) {
      RuntimeBeanReference ref = (RuntimeBeanReference) value;
      String newBeanName = resolveStringValue(ref.getBeanName());
			if (!newBeanName.equals(ref.getBeanName())) {
				return new RuntimeBeanReference(newBeanName);
			}
		}
		else if (value instanceof List) {
			visitList((List) value);
		}
		else if (value instanceof Set) {
			visitSet((Set) value);
		}
		else if (value instanceof Map) {
			visitMap((Map) value);
		}
		else if (value instanceof TypedStringValue) {
			TypedStringValue typedStringValue = (TypedStringValue) value;
			String stringValue = typedStringValue.getValue();
			if (stringValue != null) {
				String visitedString = resolveStringValue(stringValue);
				typedStringValue.setValue(visitedString);
			}
		}
		else if (value instanceof String) {
			return resolveStringValue((String) value);
		}
		return value;
	}

	protected void visitList(List listVal) {
		for (int i = 0; i < listVal.size(); i++) {
			Object elem = listVal.get(i);
			Object newVal = resolveValue(elem);
			if (!ObjectUtils.nullSafeEquals(newVal, elem)) {
				listVal.set(i, newVal);
			}
		}
	}

	protected void visitSet(Set setVal) {
		for (Iterator it = new HashSet(setVal).iterator(); it.hasNext();) {
			Object elem = it.next();
			Object newVal = resolveValue(elem);
			if (!ObjectUtils.nullSafeEquals(newVal, elem)) {
				setVal.remove(elem);
				setVal.add(newVal);
			}
		}
	}

	protected void visitMap(Map mapVal) {
		for (Iterator it = new HashMap(mapVal).entrySet().iterator(); it.hasNext();) {
			Map.Entry entry = (Map.Entry) it.next();
			Object key = entry.getKey();
			Object newKey = resolveValue(key);
			boolean isNewKey = !ObjectUtils.nullSafeEquals(key, newKey);
			Object val = entry.getValue();
			Object newVal = resolveValue(val);
			if (isNewKey) {
				mapVal.remove(key);
			}
			if (isNewKey || !ObjectUtils.nullSafeEquals(newVal, val)) {
				mapVal.put(newKey, newVal);
			}
		}
	}

	/**
	 * Resolve the given String value, for example parsing placeholders.
	 * @param strVal the original String value
	 * @return the resolved String value
	 */
	protected String resolveStringValue(String strVal) {
		if (this.valueResolver == null) {
			throw new IllegalStateException("No StringValueResolver specified - pass a resolver " +
					"object into the constructor or override the 'resolveStringValue' method");
		}
		return this.valueResolver.resolveStringValue(strVal);
	}

}